Panel a: (top) rebrightening in 2021 in the 1 − 4 keV and 4 − 10 keV, represented by red and blue curves, respectively. (bottom) Dynamic power density spectrum spanning the 1 − 10 keV range. The five red dashed lines serve to delineate four distinct epochs characterized by different timing properties. Panel b: the gaps between effective observations were eliminated, due to the extended timescale of the data, to enhance the clarity of the temporal evolution. The figure clearly reveals the presence of LFQPOs ∼0.2 Hz and high-frequency brake noise. The five dashed lines in (a) and (b) represent the same time intervals. With the gaps removed, they more clearly distinguish the four different regions in (b).